Fluorescent sensors for transition metals based on electron-transfer and energy-transfer mechanisms
Fluorescent sensors for transition metals based on electron-transfer and energy-transfer mechanisms
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DOI：
10.1002/chem.19960020114
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发表时间：
1996-01-01
影响因子：
4.3
通讯作者：
Sacchi, D
中科院分区：
文献类型：
--
作者：
Fabbrizzi, L;Licchelli, M;Sacchi, D
三维二价金属离子的荧光传感器已通过超分子方法设计：蒽片段（信号亚基）连接到环或非环四齿配体（受体）。金属-受体相互作用的发生是通过蒽荧光的猝灭来表示的。当受体（即传感器2和3的二氧化二胺亚基）能够促进金属的单电子氧化时，通过光诱导金属到荧光团的电子转移机制发生猝灭。在含有四胺结合亚基（4和5）的传感器的情况下，通过能量转移过程进行猝灭。选择性金属结合和识别可以通过改变pH值来实现，并且可以通过缓冲溶液中的荧光光谱滴定实验来区分金属离子（例如，Cu-II和Ni-II）。然而系统2、3和5表现出可逆的金属结合行为，含环香环的系统4不可逆地结合过渡金属（由于动力学大环效应），不能作为传感器正常工作。
Fluorescent sensors for 3 d divalent metal ions have been designed by means of a supramolecular approach: an anthracene fragment (the signalling subunit) has been linked to either a cyclic or a noncyclic quadridentate ligand (the receptor). Occurrence of the metal-receptor interaction is signalled through the quenching of anthracene fluorescence. When the receptor (i.e., the dioxote-tramine subunit of sensors 2 and 3) is able to promote the one-electron oxidation of the metal, quenching takes place through a photoinduced metal-to-fluorophore electron-transfer mechanism. In the case of sensors containing a tetraamine binding subunit (4 and 5), quenching proceeds by an energy-transfer process. Selective metal binding and recognition can be achieved by varying the pH, and metal ions can be distinguished (e.g., Cu-II from Ni-II) by spectrofluorimetric titration experiments in buffered solutions. Whereas systems 2, 3 and 5 show reversible metal binding behaviour, the cyclam-containing system 4 irreversibly incorporates transition metals (due to the kinetic macrocyclic effect) and cannot work properly as a sensor.